by Ken Task.
First, agree with Mary and do encourage you to re-read links she provided.
Now from my own perspective/personal experience ...
Gonna ask lots of questions cause you've not given us much to go on - don't have to respond to any particular question ... if you did it and the topic of the setup item is correct, you've double checked, etc. then move onto the next.
I take it the old plugin is this one:
https://moodle.org/plugins/auth_googleoauth2
which has:
"Plugin end of life starting from Moodle 3.3"
Used it. It worked well, but alas, things move forward ... and now Moodle has it built into core. That's a plus in my book, but, there isn't any utility to convert exisiting accouints using Google Oauth 2 old plugin to new built in Google Oauth2. ![sad sad]()
You have discovered/know about CSV for users, but in my experience with. converting a site from manual and email to a saml2 plugin discovered there were some fields one could not change via CSV file - auth field ... only if that field was already set to manual (that might have changed by now, dunno).
If you go this route (CSV) create a dummy account and work only that dummy account ... nothing global yet.
AND, don't forget to be religious about backing up your DB before a tinker session working on this.
Did you disable the old googleoath2 authentication in the your moodle?
At one time, one had to add a line to a login form ... did you remove that line or was yours the version that finally 'injected' the G+ login button on the left under the normal login boxes?
https://docs.moodle.org/35/en/OAuth_2_Google_service
Is the 'call back' URL one had to enter into Google config of the account being used for IAM authentication changed?
When you configured the new with the client key and secret, were you sure that *NO* blank spaces were either in front of the key and or secret?
Did you take the time to create or have setup an Oauth consent screen?
How about domain verification?
So what does 'does not work look like'? What happens after it's configured and you attempt to use the new?
I had, at one time, an older site that used the old and had to resort to editing the mdl_user table directly in order to keep all accounts on that system with the same ID numbers. Live site and students all ready using courses - which am guessing is your same situation.
Here's what needs to be changed in mdl_user ... from notes at that time:
In/on a Moodle 3.3 that cannot run the old plugin:
mysql> mysql> select id,auth,username,firstname,lastname,email from mdl_user where auth="oauth2";
+----+--------+------------------------+-----------+----------+------------------------+
| id | auth | username | firstname | lastname | email |
+----+--------+------------------------+-----------+----------+------------------------+
| 4 | oauth2 | mine@gmail.com | Ken | Task | mine@gmail.com
On a 3.2 that does use the **old plugin**:
mysql> select id,auth,username,firstname,lastname,email from mdl_user where auth like "google%";
+----+--------------+---------------+-----------+----------+----------------------+
| id | auth | username | firstname | lastname | email |
+----+--------------+---------------+-----------+----------+----------------------+
| 6 | googleoauth2 | social_user_1 | Ken | Task | mine@gmail.com
Note the differences
the auth column is different .. ** key to conversion is the username **
Neither had passwords in the mdl_user table ... that's a plus.
Had to do DB queries to change the values - sorry didn't record that query. :| And I've not internalized DB queries that do 'magic stuff' so am hesitant to provide one - I don't like being responsible for 'wrecking' others' Moodles! ![smile smile]()
If you take this approach to fix, do backup your database and know how to restore it before working with queries.
'spirit of sharing', Ken